Urban microclimate dataset from low-cost sensor networks in a hot and humid tropical climate: Reunion Island.

This article describes an urban microclimate dataset collected on Reunion Island, a hot and humid tropical island in the southwest Indian Ocean, between October 2024 and June 2025. Measurements were acquired from two neighborhood-scale monitoring networks installed in Saint-Denis (north coast) and Le Port (west coast), representing contrasting urban morphologies and local climatic contexts. The monitoring system was based on several LoRa communication networks connecting 25 low-cost weather stations developed by the authors and deployed on residential buildings. More than ten stations were installed in each neighborhood, providing dense spatial coverage suitable for fine-scale characterization of urban microclimate variability. This dataset contributes rare high-density urban microclimate observations for a small tropical island context. The dataset contains time series recorded at 10-minute intervals for air temperature, relative humidity, wind speed, global horizontal solar radiation, and grey globe temperature. Publicly shared files also include metadata for each station, such as geographic coordinates, deployment period, sensor grouping, network allocation, and site characteristics relevant to urban climate analyses. Quality control procedures and routine maintenance operations were performed during the monitoring campaigns, and stations with incomplete records can be identified through the metadata files. The recorded variables allow calculation of additional indicators related to thermal environment assessment, including mean radiant temperature and the Universal Thermal Climate Index, using standardized procedures and open-source tools such as the Python library pythermalcomfort. The dataset can be reused for applications related to urban overheating, outdoor thermal comfort, and neighborhood-scale climate characterization in tropical environments. It may support calibration and validation of urban climate and building-environment models such as ENVI-met or STEVE, comparison between contrasting urban forms, evaluation of heat mitigation scenarios, development of low-cost sensing approaches, and cross-comparison with datasets from other cities and climatic regions.